Kutch, high risk earthquake zone

P Rajendran

Long before Friday's earthquake occurred, seismologists had been expressing concern about the danger of one, basing their view on mountain-building activity in the area.

The area has been riven by seismic activity for millennia. Land, like a port at Sindree, has sunk below sea level; or, like the Shravan Kavadiya area near Bhuj may have, risen above it. Rivers, like the Sutlej, the Indus and possibly the Saraswati, have changed course drastically or disappeared altogether; at times huge cracks, like the Allah Bund, have scarred their way through
the countryside.

Dhola Vira, an important Harappan town, had suffered two major earthquakes in about 2700 and 2500 BC.

Dr R V Karanth of the geology department at MS University, Baroda, had pointed out the danger in a paper last year, asserting that the earthquakes in the area were a fallout of mountain-building in the area, much as in the Himalayas. He had pointed out that it had taken the Himalayas over 40 million years to rise to its present height and that it had taken about two million years for the Katrol and Kaladongar hills to rise to about 400 metres.

The Geological Survey of India has listed major faults in the area, like the Allah Bund Fault, the Banni Fault, the Katrol Hill Fault, and the Kutch Mainland Fault. Kutch falls in the seismically active Zone V area of the Indian sub-continent, making it a high risk zone for earthquakes.

But even Dr Karanth said it was unlikely that another earthquake of the nature that devastated the area in 1819 that drew the 140-km Allah Bund fault across Kutch would happen again "probably once in 2,000 years."

But Dr S N Bhattacharya, Indian Meterological Department's deputy director-general (seismology), had expressed deep concern after the high seismic activity in the area late last year. In October he had warned the Gujarat government and some agencies to build earthquake-resistant structures in seismic zones like Bhavnagar and Kutch to minimise losses during quakes.

Speaking at a workshop on 'Seismicity in Gujarat' in Baroda, he had said the design criteria for building earthquake-resistant structures in different seismic zones should get wider publicity.

In August and September, small tremors had shaken Bhavnagar; at one time there were 68 tremors in a week. People in Bhavnagar then, like people now elsewhere in Gujarat, refused to sleep under a roof.

Concern was expressed in various fora, official and not so official. In a posting at the 'Amateur Seismic Centre' on August 13, Pankaj Rajai wrote, 'We are experiencing earthquake shocks for the last 4 days in… Bhavnagar. We would like to let you know that no special instruments are available here… People here are living in terror... We really don't know what to do… No comments have come from officials here. Also, there has been no statement from the state government…'

Samir Shah of the Bharat Nagar area had said on September 18 that he had never experienced a real earthquake before the period. He claimed that fearful people had begun migrating to other cities.

On September 14, Taral Buch of Bhavnagar wrote: 'I We felt a very major tremor at 10 10.pm on the 14th of September in Bhavnagar Gujarat. It was a major one. This was 35th since 12th morning! More than 4 magnitudes…' And so on.

The warning were noted, of course, but earthquake-resistant structures may have appeared a luxury. Given the viciousness of the actual earthquake, it perhaps would not have made much difference…